Valve actuating mechanism



Sept. 3,- 1940. o. H. BANKER VALVE AGTUATING MECHANISM Filed May 13.1938 1N VENT OR. Oscarfi. 5012M LLQ ' ATTORNEY. I

Patented Sept. 3, 1940 VALVE ACTUATING MECHANISM Oscar H. Banker,Chicago, Illa Application May 13, 1938, Serial No. 207,747

13 Claims.

The invention relates generally to a valve actuating mechanism for aninternal combustion engine and more particularly to a valve lifter orsilencer for eliminating clearance in the actuating mechanism.

The general object of the invention is to provide a selft-containedvalve lifter of new and improved construction.

Another object is to provide a self-contained, hydraulic valve actuatingdevice comprising two telescopically engaged members, one for engagementwith the valve stem of a valve actuating mechanism and the other forengagement with the valve actuating cam, together with hydraulic meansof novel construction for maintaining said members extended and inengagement with said valve stem and cam and for transmitting the forcefor opening the valve.

Another object is to provide a device of this character of a new andimproved construction rendering the mechanism extremely quiet under alloperating conditions, economical to manufacture, efiicient, durable, andeasy to install either initially or as a replacement for noisy,

pressure to extend the piston andcylinder parts 1 of the device into'constant engagement with the valve stem and valve cam of the valveactuating mechanism.

Other objects and advantages will become readily apparent from thefollowing detailed description taken in connection with the accompanyingdrawing, in which:

Fig. 1 is a view partly in section of a valve actuating mechanism for aninternal combustion engine embodying features of the invention.

Fig. 2 is a fragmentary view partly in longi- 50 tudinal central sectionthrough the preferred form of the invention shown in Fig. 1..

Fig. 3 is a fragmentary plan view taken along line 33 of Fig. 2.

While the invention is disclosed in the drawing and will hereinafter bedescribed as embodied in a preferred form, it is not intended that theinvention be limited to the specific embodiment disclosed. It isintended to cover all modifications and alternative constructionsfalling within the spirit and scope of the invention as de- 5 fined inthe appended claims.

Referring to the drawing, and particularly to Fig. 1, l0 represents thecylinder block of an internal combustion engine and H represents a valvehaving a valve head l2 controlling a port 10 opening into a cylinder ofthe engine. The valve is mounted in the usual manner with its stem i3projecting slidably through a sleeve bushing it secured in the cylinderblock it. At the end. remote from the valve head, the valve stem carriesa washer I5 between which and the cylinder block In a compression spring15 is interposed to urge the valve toward seated position. The valve isopened against the action of the spring 86 at proper intervals by meansof a cam l'i formed on a camshaft 18 and acting through a valve liftergenerally designated H9. The valve lifter is guided for longitudinalreciprocatory movement in a bore 20 formed in a portion of the cylinderblock it].

The invention is directed more particularly to the valve lifter oractuating device generally designated !9, this device being of aself-contained by embodying a liquid as a cushioning means. Generally,the valve lifter comprises two telescopically engaged parts or members,one in the form of a cylinder 2| the lower and closed end 2| of which ismaintained in contact with the valve actuating cam H. The cylinder 2!has a cylindrical exterior surface also so that this member can beslidably mountedin the bore 28 of the cylinder block. The other memberis in the form of a rod or plunger 22 which is maintained in contactwith the valve stem. The rod member 22 has a piston 22' formed on itslower 40 end which is slidable in the cylinder 2! and divides thecylinder into a first or head end chamber 23 below the piston, and asecond or reserve chamber 24 above the piston. These chambers areinterconnected by means of a passageway through the piston formed byradially extending ports 25 and an axial port 26,the axial port havingan enlarged portion 27 with a beveled end 28 forming a seat for a ballcheck valve 29. This check valve is maintained in engagement with theseat by a coiled spring 30, one end of which engages the check valve andthe other end of which abuts an apertured washer 3i pressed into a re-=cess 32 in the lower end of the piston and expanded therein. The checkvalve is so arranged as to permit rapid and substantially free flow ofliquid from the reserve chamber through the passage, which includes anaperture 33 in the washer, to the head end chamber, the fit of thepiston in the cylinder being such as to permit slow leakage of fluidpast the piston from the head end chamber back to the reserve chamber.

In order to maintain the two parts of the device extended so as toeliminate clearance between the cylinder 2| and the cam H and betweenthe upper end of the rod 22 and the valve stem l3, the inventionprovides means for maintaining the liquid in the reserve chamber underpressure. As illustrated in Fig. 2, an annular member or second piston35 surrounds the rod 22 and has a rim 36 with a. sliding fit in thecylinder 2| and has a hub 31 with a sliding fit on the rod so as to forman upper wall for the reserve chamber 24. This member is preferablyformed of a material which is not affected by the liquid in the device(usually oil) and is backed by an annular metal collar 38 positionedagainst the upper surface thereof. However, the sealing member issufficiently resilient and flexible so that the pressure of the fluidmay act against the inner surfaces of the hub 31 and rim 36 and pressthese parts into contact with the rod 22 and cylinder 2|, respectively,to provide a, good seal between these parts and prevent loss of liquid.The member 35, and the liquid as well, are selected to withstand thehigh temperatures encountered. A commercial product called Neoprene,made from coal and having some of the characteristics of rubber, hasbeen found satisfactory as a material for the member 35. A very lowviscosity oil or a liquid commonly known as brake fluid because of itsuse in hydraulic brakes may be used for the liquid.

The secondary piston thus formed is forced downwardly by means of acoiled spring 39 positioned intermediate the collar 38 andan aperturedclosure 40 for the open end of the cylinder. The closure 40 ispreferably retained against movement outwardly of the cylinder by meansof a split wire ring 4| positioned in an annular recess 42 ofsemi-circular cross-section in the wall of the cylinder. The adjacentannular surface 4| on the head 40 is beveled as shown so that the actionof the spring 39 tending to move the closure outwardly causes thebeveled surface 4| to cam or expand the locking ring into the recess 4|.This permits of the use of an inexpensive plain wire ring in place ofthe usual spring type. Similarly, a split wire ring 43 is secured in anannular recess 44 of semi-circular cross-section in the rod 2| so as tolimit the outward movement of the piston in the cylinder when the deviceis removed from its position between the valve stem and valve cam, asshown in Figs. 10 and 12. Here again, the head 40 is provided with anannular beveled or cam surface 4|" which functions to contract thelocking ring and retain it in the recess 44.

In assembling the form of the invention illustrated, a suitable liquidis placed in the cylinder and the piston 22' and annular member 35 areinstalled in a way which does not trap any air below the member 35. Whenthe valve lifter is installed in an engine, as illustrated in Fig. 1,liquid under pressure in the reserve chamber is forced past the checkvalve and] into the head end chamber until the two parts of the deviceare extended sufiiciently to take up all clearance in the mechanism.During the operation of the,

engine, any leakage past the piston during the valve lifting strokes, ordue to expansion of the liquid and parts with a rise in temperature, isimmediately replaced in the head end chamber during the return strokesbecause of the pres sure maintained on the liquid in the reservechamber. Actually, this pressure need only be sufiiciently great so thatthe total pressure acting on the lower end of the piston is sufficientto overcome the pressure of atmosphere on the outer end of the pistonrod.

In a valve mechanism of the type illustrated, a valve spring such as 6(Fig. 1) is generally selected very carefully as to strength so as toinsure proper operation of the valve. In providing a valve lifter, suchas I9, for incorporation in the valve actuating mechanism, it is highlydesirable that the action of the valve lifter does not neutralize toolarge a portion of the pressure exerted by the spring 3 in maintainingthe valve 2 in its closed position. Thus, if a spring were used in sucha manner as to act directly between the cylinder 2| and the rod 22 toextend the parts into engagement with the valve cam and valve stem,respectively, such a spring must necessarily be relatively light and, asa result, would be somewhat fragile and subject to frequent breakage inview of the high speeds and vibration encountered when the engine is inoperation. In the invention as illustrated, a relatively heavy spring 39is utilized so as to obtain satisfactory operation and long life, andyetthe upward pressure exerted by the rod 22 on the valve stem, whilethe valve I2 is seated, is relatively light due to the arrangement ofthe parts. The pressure of the spring 39 is exerted upon the liquid inthe reserve reservoir through the annular member 35, and during theclosing movement of the valve I2 the pressure in the head end chamber 23is equal to the pressure in the reserve chamber 24. Since the liquid inthe reserve chamber 24 acts to move the piston 22' downwardly and theliquid in the head end chamber 23 acts to move the piston upwardly, theresultant force tending to move the piston upwardly is equivalent tothat exerted by the liquid acting on an area equal to the crosssectionalarea of the rod 22. Therodarea may be so selected that the upwardpressure on the rod is but a fraction of the total pressure exerted bythe spring 39.

It will be readily apparent that by providing the reserve chamber with amovable wall which is constantly forced in a direction to compress theliquid in the reserve chamber, as well as the head end chamber and theconnecting passage,

is completely filled with liquid under pressure.

' the engine is in operation, an unusually high back pressure is avoidedby providing the reserve chamber with a yieldable wall.

Preferably, the end wall 2| of the cylinder 2| has a flat inner surfaceand the adjacent end of the piston 22' is also flat and of large area.In the event the liquid in the device is for any reason dissipated ornone is placed therein, these contacting surfaces of the piston andcylinder endare of sufiicient area to withstand the shocks of continuedoperation of the engine, even in the absence of the usual cushioningeffect of the liquid. With the construction shown herein, it is possibleto leave an extremely small amount of clearance between the piston 22'and the closed end of the cylinder. This holds the piston to a shorttravel even in the event the liquid is lost or inadvertently left out,insuring proper opening and closing of the valve. Continued operation ofthe engine is thereby assured. Furthermore, the head end of the pistonis free from springs and other mechanisms, so that there are no fragileparts in the head end of the cylinder which would be crushed in theabsence of liquid in the device.

Openings 45 are preferably provided in the closure '19 and drainopenings 46 are provided in the sidewall of the cylinder 2| so that anyoil or other liquid which may leak from other parts of the engine intothe upper portion of the cylinder cannot remain and build up a presssurewhich will destroy the normal efiect of the coiled spring 39. Oilpassing out through the openings 46 serve to lubricate the outer surfaceof the cylinder and the bore 20.

The invention provides an extremely compact device which is able tofunction continuously even though the liquid normally contained thereinis absent. By maintaining the liquid in the reserve chamber underpressure, it is possible to utilize the liquid itself as a means forextending the parts. When a spring such as 39 is used for producing thepressure in the reserve chamber, a larger and stronger spring may beused than would be possible if the spring acted directly to extend theparts.

I claim as my invention:

l. A valve actuating device comprising, in combination, a cylinderclosed at the head end and having an apertured head at the other, apiston slidable in said cylinder and having a rod extending through saidaperture, a flexible annular member between said rod and the wall of thecylinder and cooperating therewith to form a reserve chamber outside ofthe piston, said cylinder being completely filled with liquid betweensaid fiexible member and the closed end of the cylinder, a check valvedevice permitting rapid flow of liquid from the reserve chamber to thehead end ofthe cylinder, and resilient means acting against saidflexible member to maintain the liquid in the reserve chamber underpressure sufiicient to move the piston outwardly in the cylinder.

2. A valve actuating device comprising, in combination, a cylinderclosed at the head end and having an apertured head at the other, apiston slidable in said cylinder and having a rod extending through saidaperture, an annular member between said rod and the wall of thecylinder and cooperating therewith to form a reserve chamber outside ofthe piston, said cylinder being completely filled with liquid betweensaid annular member and the closed end of the cylinder, means permittingflow of liquid from the reserve chamber to the head end of the cylinder,and means carried on the cylinder and acting against said annular.memberto maintain the liquid in the reserve chamber under pressure sufiicientto move the piston outwardly in the cylinder.

3. A valve actuating device comprising, in combination, a ,memberforming a cylinder, a piston in said cylinder having a rod projectingfrom the open end thereof, a check valve device carried on said pistonpermitting liquid to flow freely from a reserve chamber on the outsideof the piston to the head end of the cylinder and preventing reverseflow, an annular member mounted on said rod and forming one wall for thereserve chamber, an apertured closure for the open end of said cylinderthrough which the rod projects, and a. coiled spring intermediate saidannular member and closure effective to depress the annular inember andmaintain the liquid in the reserve chamber under pressure sufiicient toforce liquid into the head end of the cylinder and move the pistonoutwardly in the cylinder.

4. A valve actuating device comprising, in combination, a member forminga cylinder, a piston in said cylinder having a rod projecting from theopen end thereof, a check valve device carried on said piston permittingliquid to flow freely from a reserve chamber on the outside of thepiston to the head end of the cylinder and preventing reverse flow, anannular member slidably mounted on said rod and forming one wall for thereserve chamber, and a spring efiective to press said annular member andmaintain the liquid in the reserve chamber under pressure sufficient toforce liquid into the head end of the cylinder and move the pistonoutwardly in the cylinder.

5. In a valve operating mechanism, in combination, two telescopicallyengaged members, hydraulic resisting means between said memberscooperating therewith to permit the slow contraction and rapid extensionof the same and including a first chamber filled with liquid, a secondexpansible chamber completely filled with liquid into which liquid fromsaid first chamber leaks slowly and a check valve permitting rapidreturn of liquid from the second chamber to the first to extend saidtelescopic members, and means including a resilient device acting tocontract said second chamber for exerting pressure on the liquid thereinso as to force it past said check valve and into said first chamber andcause the extension of said members.

6. In a valve operating mechanism, in combination, two telescopicallyengaged members, hydraulic resisting means between said memberscooperating therewith to permit the slow contraction and rapid extensionof the same and including a first chamber filled with liquid, a secondexpansible chamber completely filled with liquid into which liquid fromsaid first chamber leaks slowly and a check valve permitting rapidreturn of liquid from the second chamber to the first to extend saidtelescopic members, and means associating with said second chamber forexerting pressure on the liquid therein so as to force it past saidcheck valve and into said first chamber and cause the extension of saidmembers.

7. In a valve operating mechanism, in combination, two telescopicallyengaged members, hydraulic resisting means between said memberscooperating therewith to permit the slow contraction and rapid extensionof the same and including a first chamber filled with liquid, a secondexpansible chamber completely filled with liquid into which liquid fromsaid first chamber leaks slowly and means permitting relatively rapidreturn of liquid from the second chamber to the first to extend saidtelescopic members, and means including a resilient device carried onone of said members for exerting pressure on the liquid in said secondchamber so as toforce it past said check valve and into said firstchamher and causethe extension of said members.

8. A valve actuating device comprising, in

combination, a cylinder, a piston rod, a piston cylinder into twochambers completely filled with liquid, said piston permitting sloWleakage of liquid from the first chamber into the second, meanspermitting rapid return of liquid from the second chamber to the firstto force the piston outwardly of the cylinder, and means carried on thecylinder for maintaining the liquid in said second chamber underpressure sufficient to force liquid into the first chamber and move thepiston outwardly in the cylinder.

10. A valve actuating device comprising, in combination, a memberforming a cylinder, a piston in said cylinder having a rod projectingfrom the open end thereof, means permitting liquid to flow freely from areserve chamber on the outside of the piston to the head end of thecylinder and preventing reverse flow, an annular member surrounding saidrod and forming one wall for the reserve chamber which is completelyfilled with liquid so as to exclude air, an apertured closure for theopen end of said cylinder through which the rod projects, a coiledspring intermediate said annular member and closure efiective to depressthe annular member and maintain the liquid in the reserve chamber underpressure sufiicient to force liquid into the head end of the cylinderand move the piston outwardly in the cylinder, and means for retainingsaid closure in said cylinder comprising an annular recess in thecylinder, a split -\vire :ring positioned partly in said recess and abeveled annular surface on said closure engaging said ring and actingunder the force of said spring to expand the ring against the cylinder.

11. A valve actuating device comprising, in combination, a memberforming a cylinder, a piston in said cylinder having a rod projectingfrom the open end thereof, means permitting liquid to flow freely from areserve chamber on the outside of the piston to the head end of thecylinder and preventing reverse flow, an annular member surrounding saidrod and forming one wall for the reserve chamber which is completelyfilled with liquid, an apertured closure for the open end of saidcylinder through which the rod projects, a coiled spring intermediatesaid annular member and closure effective to depress the annular memberand maintain the liquid in the reserve chamber under pressure sufiicientto force liquid into the head end of the cylinder and move the pistonoutwardly in the, cylinder, and means for limiting the outward movementof the rod through said closure when the device is removed from anengine comprising an annular recess in said rod within the closure, asplit wire ring in said recess and an annular beveled surface on saidclosure arranged to engage said ring when the rod moves outwardly.

12. A valve actuating device comprising, in

combination, a member forming a cylinder, a

piston in said cylinder having a rod projecting from the open endthereof, means permitting liquid to flow freely from a reserve chamberon the outside of the piston to the head end of the cylinder andpreventing reverse flow, an annular member surrounding said rod andforming one wall for the reserve chamber which is completely filled withliquid, an apertured closure for the open end of said cylinder throughwhich the rod projects, a coiled spring intermediate said annular memberand closure effective to depress the annular member and maintain theliquid in the reserve chamber under pressure sufficient to force liquidinto the head end of the cylinder and move the piston outwardly in thecylinder, means for retaining said closure in said cylinder comprisingan annular recess in the cylinder, a split wire ring positioned partlyin said recess and a beveled annular surface on said closure engagingsaid ring and acting under the force of said spring to expand the ringagainst the cylinder, and means for limiting'the outward movement of therod through said closure when the device is removed from an enginecomprising an annular recess in said rod within the closure, a splitwire ring in said recess and an annular beveled surface on said closurearranged to engage said ring when the rod moves outwardly.

13. A valve actuating device comprising, in combination, a memberforming a cylinder, a piston in said cylinder having a part projectingin the cylinder and from the open end thereof, a check valve devicecarried on said piston permitting liquid to flow freely from a reservechamber on one side of the piston to the head end of the cylinder on theother side of the piston and preventing reverse flow, a member slidablymounted on the projecting part of the piston and forming one wall forthe reserve chamber, and a spring supported within the cylinder andeffective to press said member in a direction to contract the reservechamber and maintain the liquid in the reserve chamber under pressuresufficient to force liquid into the head end of the cylinder and movethe piston outwardly in the cylinder.

OSCAR H. BANKER.

